Photoresist composition and method of manufacturing a color filter substrate by using the same

ABSTRACT

A photoresist composition includes a coloring agent, a binder resin, a cross-linker, a photo-polymerization initiator and a solvent. The coloring agent includes an anthraquinone-based dye and a pigment. A color filter formed from the photoresist composition has a relatively greater light-transmittance. Thus, a contrast of a display apparatus having the color filter may be improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Korean Patent Application No.2006-62860 filed on Jul. 5, 2006, the contents of which are hereinincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photoresist composition and a methodof manufacturing a color filter substrate by using the photoresistcomposition. More particularly, the present invention relates to aphotoresist composition capable of improving a contrast of a displayapparatus and a method of manufacturing a color filter substrate byusing the photoresist composition.

2. Description of the Related Art

In general, a liquid crystal display (LCD) apparatus displays an imageby using optical and electrical properties of the liquid crystal, suchas an anisotropic refractive index, an anisotropic dielectric constant,etc. The LCD apparatus has characteristics, for example, such as a lightweight, lower power consumption, lower driving voltage, etc., incomparison with a display apparatus such as a cathode ray tube, a plasmadisplay panel, and so on.

The LCD apparatus includes a liquid crystal layer interposed betweenglass substrates. Light generated by a light source passes through theliquid crystal layer, and the liquid crystal layer controls atransmittance of the light. The light having passed through the liquidcrystal layer passes a color filter layer. A full color is displayedusing an additive mixture of the light or a subtractive mixture of thelight.

In general, the color filter layer includes a binder resin and apigment. For example, when the color filter layer has a red colorfilter, a green color filter, and a blue color filter, the red, greenand blue color filters respectively includes a red pigment, a greenpigment, and a blue pigment. The color filter layer may further includea yellow pigment, a violet pigment, etc. to effectively display a color.Since a size of the pigment is relatively large, the pigment scattersthe light passing through the color filter layer. Thus, the brightnessand a contrast of the LCD apparatus are reduced.

SUMMARY

The present invention provides a photoresist resin composition capableof improving a contrast of a display apparatus.

The present invention also provides a method of manufacturing a colorfilter substrate by using the above-mentioned photoresist resincomposition.

In one aspect of the present invention, a photoresist compositionincludes a coloring agent, a binder resin, a cross-linker, aphoto-polymerization initiator and a solvent. The coloring agentincludes an anthraquinone-based dye and a pigment.

The anthraquinone-based dye may include a compound represented by thefollowing Chemical Formula (1):

wherein R₁ and R₂ independently represent one selected from the groupconsisting of an amine group, a hydroxyl group and a halogen atom, andR₃, R₄, R₅ and R₆ independently represent an alkyl group having 1 to 4carbon atoms, and n is a natural number.

Particularly, the anthraquinone-based dye may include a compoundrepresented by the following Chemical Formula (2):

A content of the coloring agent may be about 10% to about 60% by weightbased on the total weight of the photoresist composition. A content ofthe anthraquinone-based dye may be about 5% to about 50% by weight basedon a total weight of the coloring agent. Furthermore, theanthraquinone-based dye may have a maximum ultraviolet (UV) rayabsorbance in a range between about 525 nm and about 535 nm.

For example, the binder resin may include at least one selected from thegroup consisting of a phenol-based polymer and an acryl-based polymer.The pigment may include an organic pigment.

The photoresist composition may further include an additive including atleast one selected from the group consisting of a surfactant, apigment-dispersing agent and an adhesive. A content of the additive maybe about 1% to about 3% by weight based on the total weight of thephotoresist composition.

In another aspect of the present invention, there is provided a methodof manufacturing a color filter substrate. In the method, alight-blocking layer is formed on a base substrate. A photoresistcomposition is coated on the base substrate to form a photoresist film.The photoresist composition includes a binder resin, a cross-linker, aphoto-polymerization initiator, a solvent and a coloring agent having ananthraquinone-based dye and a pigment. The photoresist film isselectively exposed to light. The photoresist film exposed to the lightis developed to form a color filter pattern.

According to the above, a color filter formed from the photoresistcomposition has a relatively great light-transmittance. Thus, a contrastof a display apparatus having the color filter may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other advantages of the present invention will becomereadily apparent by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a graph showing a contrast of each photoresist film formedfrom photoresist compositions of Example 1 and Comparative Example 1;and

FIGS. 2 to 6 are cross-sectional views illustrating a method ofmanufacturing a color filter substrate according to an embodiment of thepresent invention.

DETAILED DESCRIPTION

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which embodiments of the invention are shown.This invention may, however, be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete, and will convey the scope of the invention tothose skilled in the art. In the drawings, the sizes and relative sizesof layers and regions may be exaggerated for clarity.

It will be understood that when a member or layer is referred to asbeing “on,” “connected to” or “coupled to” another member or layer, itcan be directly on, connected or coupled to the other member or layer orintervening members or layers may be present. In contrast, when a memberis referred to as being “directly on,” “directly connected to” or“directly coupled to” another member or layer, there are no interveningmembers or layers present. Like numbers refer to like membersthroughout. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various members, components, regions, layersand/or sections, these members, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one member, component, region, layer or section fromanother region, layer or section. Thus, a first member, component,region, layer or section discussed below could be termed a secondmember, component, region, layer or section without departing from theteachings of the present invention.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one member or feature's relationship to another member(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, members described as “below” or “beneath” othermembers or features would then be oriented “above” the other members orfeatures. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, members,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, members,components, and/or groups thereof.

Embodiments of the invention are described herein with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures) of the invention. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, embodiments of the invention should not be construed aslimited to the particular shapes of regions illustrated herein but areto include deviations in shapes that result, for example, frommanufacturing. For example, an implanted region illustrated as arectangle will, typically, have rounded or curved features and/or agradient of implant concentration at its edges rather than a binarychange from implanted to non-implanted region. Likewise, a buried regionformed by implantation may result in some implantation in the regionbetween the buried region and the surface through which the implantationtakes place. Thus, the regions illustrated in the figures are schematicin nature and their shapes are not intended to illustrate the actualshape of a region of a device and are not intended to limit the scope ofthe invention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Photoresist Composition

In accordance with an embodiment of the present invention, a photoresistcomposition includes a coloring agent, a binder resin, a cross-linker, aphoto-polymerization initiator and a solvent. The coloring agentincludes an anthraquinone-based dye and a pigment.

The binder resin may include a hydroxyl aromatic polymer that is solublein an alkaline solution such as an alkaline developing solution and isnot soluble in water.

The binder resin may be cross-linked with each other by thecross-linker. The binder resin is soluble in the alkaline solutionbefore the binder resin is cross-linked to each other. However, thebinder resin is not soluble in the alkaline solution after the binderresin is cross-linked with each other.

Examples of the binder resin may include a phenol-based polymer, anacryl-based polymer, etc. The phenol-based polymer may be synthesized bypolymerizing aldehyde-based compound and phenol-based compound. Examplesof the phenol-based compound may include ortho-cresol, meta-cresol,2,4-xylenol, 2,5-xylenol, 3,4-xylenol, novolak derived therefrom, etc.These can be used alone or in a mixture thereof. Particularly, examplesof the binder resin may include poly(vinyl phenol) such aspoly(para-hydroxystyrene), poly(para-hydroxy-α-methylstyrene), etc., acopolymer polymerized from para-hydroxystyrene,para-hydroxy-α-methylstyrene, acetoxystyrene, acrylic acid, methacrylicacid, etc., hydroxyphenyl carbonyl copolymer, novolak/poly(vinyl phenol)copolymer, etc. These can be used alone or in a mixture thereof.

For example, a content of the binder resin may be about 5% to about 40%by weight based on a total weight of the photoresist composition. Whenthe content of the binder resin is less than about 5% by weight, aphotoresist film formed from the photoresist composition may have arelatively low stability of shape. When the content of the binder resinis more than about 40% by weight, the thickness of the photoresist filmformed from the photoresist composition may not be uniform.

The cross-linker may include an oligomer capable of cross-linking thebinder resin with each other. The binder resin in an exposed area iscross-linked with each other to be insoluble in an alkaline solution.Thus, a photoresist film may be patterned to form a photoresist pattern.

Examples of the cross-linker may include an aminoplast and an aminecompound, such as urea, melamine, glycol urea, etc. Particularly,examples of the cross-linker may include urea-formaldehyde oligomer,melamine-formaldehyde oligomer, benzoguanamine-formaldehyde oligomer,glycoluril-formaldehyde oligomer, hexa(methoxymethyl)melamine oligomer,etc. Among the above, hexa(methoxymethyl)melamine oligomer may bepreferable.

For example, a content of the cross-linker may be about 1% to about 15%by weight based on the total weight of the photoresist composition. Whenthe content of the cross-linker is less than about 1% by weight, thepolymerization degree of the photoresist film formed from thephotoresist composition may be relatively low. When the content of thecross-linker is more than about 15% by weight, a manufacturing cost mayincrease.

The photo-polymerization initiator may initiate polymerization of thecross-linker when exposed to light.

Examples of the photo-polymerization initiator may include atriazine-based compound, an acetophenone-based compound, axanthone-based compound, a benzoin-based compound and an imidazole-basedcompound.

Examples of the triazine-based compound may include2,4-bis(trichloromethyl)-6-p-methoxystyril-s-triazine,2-p-methoxystyril-4,6-bis-trichloromethyl-s-triazine,2,4-trichloromethyl-6-triazine,2-(2-bromo-4-methylphenyl)-4,6-bis(trichloromethyl)-s-triazine, etc.When the triazine-based compound is exposed to light, a halogen gas maybe generated to damage, for example, a mask, and to deteriorate alight-transmittance of the photoresist film formed from the photoresistcomposition. Thus, a content of the triazine-based compound may bepreferably less than about 1% by weight based on the total weight of thephotoresist composition.

Examples of the acetophenone-based compound may include benzophenone,p-(dimethylamino)benzophenone, 2,2-dichloro-4-phenoxyacetophenone,4,4-bis(dimethylamino)benzophenone, 2,2-diethoxyacetophenone,2,2-dibutoxyacetophenone, 2-hydroxy-2-methylproliophenone,p-t-butyltrichloroacetophenone, etc. Furthermore, examples of thexanthone-based compound may include xanthone, thioxanthone, 2-methylthioxanthone, 2-isobutylthioxanthone, 2-dodecylthioxanthone,2,4-dimethylthioxanthone, etc.

Examples of the benzoin-based compound may include benzoin, benzoinethyl ether, benzoin methyl ether, benzoin propyl ether, t-butyl benzoylether, etc.

Examples of the imidazole-based compound may include2,2-bis-2-chlorophenyl-4,5,4,5-tetraphenyl-2-1,2-biimidazole,2,2-bis(2,4,6-tricyanophenyl)-4,4,5,5-tetraphenyl-1,2-biimidazole, etc.

For example, a content of the photo-polymerization initiator may beabout 0.5% to about 5% by weight based on the total weight of thephotoresist composition. When the content of the photo-polymerizationinitiator is less than about 0.5% by weight, the polymerization degreeof the photoresist film formed from the photoresist composition may berelatively low. When the content of the photo-polymerization initiatoris more than about 5% by weight, light-absorbance of the photoresistfilm may be excessively increased so that the polymerization degree of alower portion of the photoresist film is relatively low.

Examples of the pigment may include an organic pigment and a non-organicpigment. Particularly, examples of the organic pigment may include C.I.pigment yellow 83, C.I. pigment yellow 150, C.I. pigment yellow 138,C.I. pigment yellow 128, C.I. pigment orange 43, C.I. pigment red 177,C.I. pigment red 202, C.I. pigment red 209, C.I. pigment red 254, C.I.pigment red 255, C.I. pigment green 7, C.I. pigment green 36, C.I.pigment blue 15, C.I. pigment blue 15:3, C.I. pigment blue 15:4, C.I.pigment blue 15:6, C.I. pigment violet 23, C.I. pigment black 1, C.I.pigment black 7, etc. Examples of the non-organic pigment may includetitanium oxide, titanium black, carbon black, etc. These can be usedalone or in a mixture thereof to mix colors.

The anthraquinone-based dye has relatively great heat-resistance andlight-resistance. The anthraquinone-based dye may include a compoundrepresented by the following Chemical Formula (1):

wherein R₁ and R₂ independently represent one selected from the groupconsisting of an amine group, a hydroxyl group and a halogen atom, andR₃, R₄, R₅ and R₆ independently represent an alkyl group having 1 to 4carbon atoms, and n is a natural number.

For example, the anthraquinone-based dye may have a maximum ultraviolet(UV) ray absorbance in a range between about 525 nm and about 535 nm.Furthermore, the anthraquinone-based dye may have a minimum UV rayabsorbance in a range between about 495 nm and about 505 nm.

A content of the anthraquinone-based dye may be about 5% to about 50% byweight based on a total weight of the coloring agent. A content of thecoloring agent may be about 10% to about 60% by weight based on thetotal weight of the photoresist composition. When the content of theanthraquinone-based dye is less than about 5% by weight based on thetotal weight of the coloring agent, light-transmittance of thephotoresist film formed from the photoresist composition may not besubstantially increased. When the content of the anthraquinone-based dyeis more than about 50% by weight, the heat-resistance and thelight-resistance of the photoresist film may be reduced. When thecontent of the coloring agent is less than about 10% by weight based onthe total weight of the photoresist composition, a color of thephotoresist film may be relatively pale. When the content of thecoloring agent is more than about 60% by weight, the light-transmittanceof the photoresist film may be reduced.

Examples of the solvent include alcohols such as methanol and ethanol,ethers such as tetrahydrofurane, glycol ethers such as ethylene glycolmonomethyl ether and ethylene glycol monoethyl ether, ethylene glycolalkyl ether acetates such as methyl cellosolve acetate and ethylcellosolve acetate, diethylene glycols such as diethylene glycolmonomethyl ether, diethylene glycol monoethyl ether and diethyleneglycol dimethyl ether, propylene glycol monoalkyl ethers such aspropylene glycol methyl ether, propylene glycol ethyl ether, propyleneglycol propyl ether and propylene glycol butyl ether, propylene glycolalkyl ether acetates such as propylene glycol methyl ether acetate,propylene glycol ethyl ether acetate, propylene glycol propyl etheracetate and propylene glycol butyl ether acetate, propylene glycol alkylether propionates such as propylene glycol methyl ether propionate,propylene glycol ethyl ether propionate, propylene glycol propyl etherpropionate and propylene glycol butyl ether propionate, aromaticcompounds such as toluene and xylene, ketones such as methyl ethylketone, cyclohexanone and 4-hydroxy 4-methyl 2-pentanone, and estercompounds such as methyl acetate, ethyl acetate, propyl acetate, butylacetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy 2-methylpropionate, ethyl 2-hydroxy 2-methyl propionate, methyl hydroxyacetate,ethyl hydroxyacetate, butyl hydroxyacetate, methyl lactate, ethyllactate, propyl lactate sulfate, butyl lactate, methyl3-hydroxypropionate, ethyl 3-hydroxypropionate, propyl3-hydroxypropionate, butyl 3-hydroxypropionate, methyl 2-hydroxy3-methyl butanoate, methyl methoxy acetate, ethyl methoxy acetate,propyl methoxy acetate, butyl methoxy acetate, methyl ethoxy acetate,ethyl ethoxy acetate, propyl ethoxy acetate, butyl ethoxy acetate,methyl propoxy acetate, ethyl propoxy acetate, propyl propoxy acetate,butyl propoxy acetate, methyl butoxy acetate, ethyl butoxy acetate,propyl butoxy acetate, butyl butoxy acetate, methyl 2-methoxypropionate,ethyl 2-methoxypropionate, propyl 2-methoxypropionate, butyl2-methoxypropionate, methyl 2-ethoxypropionate, ethyl2-ethoxypropionate, propyl 2-ethoxypropionate, butyl 2-ethoxypropionate,methyl 2-butoxypropionate, ethyl 2-butoxypropionate, propyl2-butoxypropionate, butyl 2-butoxypropionate, methyl3-methoxypropionate, ethyl 3-methoxypropionate, propyl3-methoxypropionate, butyl 3-methoxypropionate, methyl3-ethoxypropionate, ethyl 3-ethoxypropionate, propyl 3-ethoxypropionate,butyl 3-ethoxypropionate, methyl 3-propoxypropionate, ethyl3-propoxypropionate, propyl 3-propoxypropionate, butyl3-propoxypropionate, methyl 3-butoxypropionate, ethyl3-butoxypropionate, propyl 3-butoxypropionate, butyl 3-butoxypropionate,etc. These solvents can be used alone or in a mixture thereof. Among theabove, glycol ethers, ethylene glycol alkyl ether acetates anddiethylene glycols are preferably used in view of solubility andreactivity of the components composing the photoresist composition and amanufacturing condition of a coating layer.

For example, a content of the solvent may be about 20% to about 70% byweight based on the total weight of the photoresist composition. Whenthe content of the solvent is less than about 20% by weight, theviscosity of the photoresist composition may be increased so that thethickness of the photoresist film formed from the photoresistcomposition is not uniform. When the content of the solvent is more thanabout 70% by weight, the thickness of the photoresist film may berelatively small.

The photoresist composition may further include an additive, such as asurfactant, a pigment-dispersing agent, an adhesive, etc. A content ofthe additive may be about 1% to about 3% by weight based on the totalweight of the photoresist composition. When the content of the additiveis less than about 1% by weight, an adhering characteristic of thephotoresist film formed from the photoresist composition may bedeteriorated. When the content of the additive is more than about 3% byweight, the photoresist film may be non-uniformly developed.

The surfactant may serve to improve a coating characteristic and/or adeveloping characteristic of the photoresist composition. Examples ofthe surfactant may include polyoxyethylene octylphenyl ether,polyoxyethylene nonylphenyl ether, F171 (trade name; manufactured byDainippon Ink and Chemicals, Inc. of Japan), F172 (trade name;manufactured by Dainippon Ink and Chemicals, Inc. of Japan), F173 (tradename; manufactured by Dainippon Ink and Chemicals, Inc. of Japan), FC430(trade name; manufactured by Sumitomo 3M, Ltd. of Japan), FC431 (tradename; manufactured by Sumitomo 3M, Ltd. of Japan), KP341 (trade name,manufactured by Shin-Etsu Chemical Co., Ltd. of Japan), etc.

Examples of the pigment-dispersing agent may include a salt and anamide, which are formed by reacting polyalkyleneimine and polyesterhaving a free carboxyl group, polycarboxylic acid ester, unsaturatedpolyamide, polycarboxylic acid, an amine salt of polycarboxylic acid, anammonium salt of polycarboxylic acid, an amine salt of polyalkylcarboxylic acid, polysiloxane, polycarboxylic acid ester having ahydroxyl group, derivatives thereof, (meta)acrylic acid/styrenecopolymer, (meta)acrylic acid/(meta)acrylic acid ester copolymer,styrene/maleic acid copolymer, polyvinyl alcohol, polyvinyl pyrrolidone,etc. These pigment-dispersing agents can be used alone or in a mixturethereof.

The adhesive may serve to reinforce an adhesion between a substrate andthe photoresist film formed from the photoresist composition. Examplesof the adhesive may include γ-methacryl propyl trimethoxy silane, vinyltriacetoxy silane, vinyl trimethoxy silane, γ-isocyanate propyltriethoxy silane, γ-glycidoxy propyl trimethoxy silane, β-(3,4-epoxycyclohexyl)ethyl trimethoxy silane, etc. These adhesives can be usedalone or in a mixture thereof.

The photoresist composition may be coated on the substrate through aspraying method, a roll coater method, a spin coating method, etc., andmay be then pre-baked to form a photoresist film.

The present invention will be explained more fully hereinafter withreference to an example and a comparative example.

EXAMPLE 1

About 200 g of propylene glycol methyl ether propionate as a solvent,about 100 g of meta-cresol/formaldehyde novolak resin, of whichmolecular weight is about 6,000 [weight-average molecular weight(Mw)/number-average molecular weight (Mn)=1.69] as a binder resin, about10 g of hexa(methoxymethyl)melamine oligomer as a cross-linker, about3.0 g of benzophenone as a photo-polymerization initiator and about 36 gof C.I. pigment blue 15:6 and about 4 g of a compound represented byfollowing Chemical Formula (2) as a coloring agent were mixed with eachother. The mixture was stirred and filtered to prepare a photoresistcomposition.

COMPARATIVE EXAMPLE 1

About 200 g of propylene glycol methyl ether propionate as a solvent,about 100 g of meta-cresol/formaldehyde novolak resin, of whichmolecular weight is about 6,000 [weight-average molecular weight(Mw)/number-average molecular weight (Mn)=1.69] as a binder resin, about10 g of hexa(methoxymethyl)melamine oligomer as a cross-linker, about3.0 g of benzophenone as a photo-polymerization initiator and about 36 gof C.I. pigment blue 15:6 and about 4 g of C.I. pigment violet 23 as acoloring agent were mixed with each other. The mixture was stirred andfiltered to prepare a photoresist composition.

Experiment Evaluation of Characteristics of Photoresist Compositions

Each of the photoresist compositions of Example 1 and ComparativeExample 1 was coated on a substrate and was baked to form photoresistfilms. A heat-resistance, a light-resistance, brightness and a color ofeach of the photoresist films were measured as follows. The brightnessand the color of each of the photoresist films were measured using areflective spectrophotometer and/or a transmissive spectrophotometeraccording to a standard colorimetric system of Commission Internationalede I'Eclairage (CIE). Particularly, the brightness, a blue x-coordinatevalue of a color coordinate system and a blue y-coordinate value of thecolor coordinate system were measured.

Furthermore, a first color-changing rate ΔE1 of each of the photoresistfilms were measured after having been heated at a temperature of about230° C. for about two hours. A second color-changing rate ΔE2 of each ofthe photoresist films were measured after having been exposed to a xenonlamp for about 200 hours. The first and second color-changing rates ΔE1and ΔE2 were obtained by calculating values measured according to CIEL-a-b colorimetric system by using the following formula:ΔE=[(ΔL)²+(Δa)²+(Δb)²]^(1/2)

Thus obtained results are illustrated in the following Table 1.

TABLE 1 thickness(μm) Y x y ΔE1 ΔE2 Comparative 1.29 9.73 0.138 0.0962.62 1.16 Example 1 0.87 15.03 0.142 0.125 1.79 0.61 0.74 17.86 0.1460.139 2.2 0.63 Example 1 1.38 13.99 0.137 0.132 3.82 1.35 0.92 20.890.145 0.164 2.93 1.39 0.77 24.51 0.151 0.179 2.55 1.69

FIG. 1 is a graph showing a contrast of each of the photoresist filmsformed from the photoresist compositions of Example 1 and ComparativeExample 1. Each rectangular spot represents a contrast of thephotoresist film formed from the photoresist composition of Example 1,and each triangular spot represents a contrast of the photoresist filmformed from the photoresist composition of Comparative Example 1. Acontinuous line represents a linear regression line based on thecontrast of the photoresist film formed from the photoresist compositionof Example 1. A dotted line represents a linear regression line based onthe contrast of the photoresist film formed from the photoresistcomposition of Comparative Example 1. A vertical axis of the graphcorresponds to the contrast value. A horizontal axis of the graphcorresponds to the blue y-coordinate value of the color coordinatesystem.

Referring to Table 1 and FIG. 1, the brightness of the photoresist filmformed from the photoresist composition of Example 1 was greater thanthe brightness of the photoresist film formed from the photoresistcomposition of Comparative Example 1. Thus, it can be noted that alight-transmittance of the photoresist film formed from the photoresistcomposition of Example 1 is greater than a light-transmittance of thephotoresist film formed from the photoresist composition of ComparativeExample 1.

The heat-resistance and the light-resistance of the photoresist filmformed from the photoresist composition of Example 1 was smaller thanthe heat-resistance and the light-resistance of the photoresist filmformed from the photoresist composition of Comparative Example 1.However, the heat-resistance and the light-resistance of the photoresistfilm formed from the photoresist composition of Example 1 are relativelygreat in comparison with a practically available range of theheat-resistance and the light-resistance.

The contrast of the photoresist film formed from the photoresistcomposition of Example 1 was greater than the contrast of thephotoresist film formed from the photoresist composition of ComparativeExample 1. For example, when a value of the horizontal axis of FIG. 2was about 0.09, a vertical value of the continuous line was about 2243,and a vertical value of the dotted line was about 1591.

Method of Manufacturing a Color Filter Substrate

FIGS. 2 to 6 are cross-sectional views illustrating a method ofmanufacturing a color filter substrate according to an embodiment of thepresent invention.

Referring to FIG. 2, a light-blocking layer 202 is formed on a basesubstrate 201. Examples of a material that may be used for thelight-blocking layer 202 include chrome, chrome oxide, an organicmaterial containing a black pigment, etc.

Referring to FIG. 3, a photoresist composition is coated on the basesubstrate 201 having the light-blocking layer 202 to form a photoresistfilm 203. The photoresist composition includes a coloring agent, abinder resin, a cross-linker, a photo-polymerization initiator and asolvent. The coloring agent includes an anthraquinone-based dye and apigment.

For example, the anthraquinone-based dye may have a maximum ultraviolet(UV) ray absorbance in a range between about 525 nm and about 535 nm.Furthermore, the anthraquinone-based dye may include a compoundrepresented by the following Chemical Formula (1):

wherein R₁ and R₂ independently represent one selected from the groupconsisting of an amine group, a hydroxyl group and a halogen atom, andR₃, R₄, R₅ and R₆ independently represent an alkyl group having 1 to 4carbon atoms, and n is a natural number.

The photoresist composition may be coated on the substrate through aspraying method, a roll coater method, a spin coating method, etc.

The photoresist film 203 is post-baked to remove a portion of thesolvent in the photoresist film 203 without decomposing the binderresin. In one example, a thickness of the photoresist film 203 may be nomore than about 2 μm after the photoresist film 203 is post-baked.

A mask having a predetermined pattern is positioned on a mask stage ofan exposure apparatus, and then the mask is arranged over thephotoresist film 203 in an alignment process. An illumination light isirradiated onto the mask for a desirable time so that a portion of thephotoresist film 203 is exposed to the light through the mask.

Examples of the light may include a G-line ray, an I-line ray, a kryptonfluoride laser, an argon fluoride laser, an electron beam, an X-ray,etc. The I-line ray or the G-line ray may be preferably used as thelight. In an exposure process, an exposed portion of the photoresistfilm 203 may have a solubility substantially different from a solubilityof an unexposed portion of the photoresist film 203.

Referring to FIG. 4, the unexposed portion of the photoresist film 203is removed using a developing solution to form a color filter pattern204. The color filter pattern 204 may cover a portion of thelight-blocking layer 202.

Referring to FIG. 5, a protecting layer 205 is formed on thelight-blocking layer 202 and the color filter pattern 204. Theprotecting layer 205 protects the light-blocking layer 202 and the colorfilter pattern 204. Examples of a material that may be used for theprotecting layer 205 include silicon oxide, silicon nitride, an organicmaterial, etc.

Referring to FIG. 6, a transparent conductive layer (not shown) isformed on the protecting layer 205. Examples of a material that may beused for the transparent conductive layer include indium tin oxide(ITO), indium zinc oxide (IZO), etc. The transparent conductive layer ispatterned through a photolithography process to form a common electrodelayer 206.

According to the above, a photoresist composition includes a mixture ofan anthraquinone-based dye and a pigment as a coloring agent, and acolor filter formed from the photoresist composition has a relativelygreater light-transmittance. Thus, a contrast of a display apparatushaving the color filter may be improved.

Although embodiments of the present invention have been described, it isunderstood that the present invention should not be limited to theseembodiments but various changes and modifications can be made by oneordinary skilled in the art within the spirit and scope of the presentinvention as hereinafter claimed.

1. A photoresist composition, comprising: a coloring agent including ananthraquinone-based dye and a pigment, wherein the anthraguinone-baseddye includes a compound represented by the following Chemical Formula(1):

wherein R₁ and R₂ independently represent one selected from the groupconsisting of an amine group, a hydroxyl group and a halogen atom, andR₃, R₄, R₅ and R₆ independently represent an alkyl group having 1 to 4carbon atoms, and n is a natural number; a binder resin; a cross-linker;a photo-polymerization initiator; and a solvent.
 2. A photoresistcomposition, comprising: a coloring agent including ananthraquinone-based dye and a pigment, wherein the anthraquinone-baseddye includes a compound represented by the following Chemical Formula(2):

a binder resin; a cross-linker, a photo-polymerization initiator; and asolvent.
 3. The photoresist composition of claim 1, wherein the coloringagent is about 10% to about 60% by weight based on a total weight of thephotoresist composition.
 4. The photoresist composition of claim 3,wherein the anthraquinone-based dye is about 5% to about 50% by weightbased on a total weight of the coloring agent.
 5. The photoresistcomposition of claim 4, wherein the anthraquinone-based dye has amaximum ultraviolet (UV) ray absorbance in a range between about 525 nmand about 535 nm.
 6. The photoresist composition of claim 1, wherein thebinder resin includes at least one selected from the group consisting ofa phenol-based polymer and an acryl-based polymer.
 7. The photoresistcomposition of claim 1, wherein the pigment includes an organic pigment.8. The photoresist composition of claim 1, further comprising anadditive that includes at least one selected from the group consistingof a pigment-dispersing agent, an adhesive and a surfactant.
 9. Thephotoresist composition of claim 8, wherein the additive is about 1% toabout 3% by weight based on a total weight of the photoresistcomposition.
 10. A method of manufacturing a color filter substrate, themethod comprising: coating a photoresist composition on a base substrateto form a photoresist film, the photoresist composition including abinder resin, a cross-linker, a photo-polymerization initiator, asolvent and a coloring agent having an anthraquinone-based dye and apigment, wherein the anthraguinone-based dye includes a compoundrepresented by the following Chemical Formula (1):

wherein R₁ and R₂ independently represent one selected from the groupconsisting of an amine group, a hydroxyl group and a halogen atom, andR₃,R₄,R₅ and R₆ independently represent an alkyl group having 1 to 4carbon atoms, and n is a natural number; selectively exposing thephotoresist film to light; and developing the photoresist film exposedto the light to form a color filter pattern.
 11. The method of claim 10,wherein the anthraquinone-based dye includes a compound represented bythe following Chemical Formula (2):


12. The method of claim 10, wherein the anthraquinone-based dye has amaximum ultraviolet (UV) ray absorbance in a range between about 525 nmand about 535 nm.
 13. The method of claim 10, further comprising forminga protecting layer covering the color filter pattern and thelight-blocking layer.
 14. The method of claim 13, further comprisingforming a common electrode layer on the protecting layer.